The first question is that you list the remainder after dividing the first few numbers by 3, and you will find that the arrangement of the remainder is as follows:

0,2,2, 1,0, 1, 1,2,0,2,2, 1,0, 1, 1,2

That is to say, every eight numbers will be repeated, and three of every eight numbers have the remainder 1.

1995 divided by 8=249 remainder 3

The remainder 3 indicates that there are still three digits. According to the following rules, it is found that the remainder of the first three digits in each group is not 1.

So 1 divided by 3 is 249*3=747.

The same method can be used to calculate the law that every 16 numbers will be repeated.

2005/ 16= 125 remainder 5

The remainder of the 2005th bit can be calculated as 6 as the remainder of the 5th bit.

In a word, the key to this topic is to find the law.